Path tracking anti-saturation robust control method for under-actuated water surface ship

Abstract

The invention belongs to the technical field of path tracking control of under-actuated water surface ships, and particularly relates to a path tracking anti-saturation robust control method of an under-actuated water surface ship. According to the method, an error-limited sideslip compensation ECS-LOS guide law is designed, and a sideslip estimator is adopted to compensate a time-varying sideslipangle. According to the method, a path tracking robust controller is designed through a backstepping method, an interference observer is adopted to observe unknown synthetic interference in a system,and a saturation compensator is introduced into the designed robust controller in order to avoid the saturation phenomenon of an actuator. According to the method, the expected path can be tracked atthe expected speed on the premise that the under-actuated water surface ship does not violate the error limitation requirement and the actuator does not exceed the saturation range under the conditions of model uncertainty, unknown external environment interference, time-varying sideslip, tracking error limitation and actuator input saturation; and tracking errors can be converged near zero, so that the tracking precision is higher.

Description

technical field [0001] The invention belongs to the technical field of path tracking control of underactuated surface ships, and in particular relates to a path tracking anti-saturation robust control method of underactuated surface ships. Background technique [0002] Due to the complexity of the environment and the requirements of operational accuracy, in the path tracking control of underactuated surface ships, not only the tracking performance of the desired path must be considered, but also the tracking error of the ship during navigation must not have large jitter, otherwise it will be unfavorable. The precise path tracking of the ship, so the tracking error constraint problem should be considered in the path tracking control. From a practical engineering point of view, when a ship needs to pass through a narrow channel, the route of the ship should be limited between the boundaries on both sides of the channel, otherwise, the ship will easily collide with the channel,...

AI Technical Summary

Problems solved by technology

In most of the current literature, the ship path tracking control only realizes the local exponential stability of the control system or the consistent final boundedness of the closed-loop signal under the uncertain model and external environment disturbance, without considering the tracking error constraint problem. In other words, most of the literature only qualitatively analyzes the path tracking error without quantitative constraints

In addition, the actuator input saturation of underactuated surface ships is an objective problem, because the actuators have physical limitations, and the force and torque they can provide are limited

However, most of the existing ship path tracking control research results assume that the actuator can provide ideal force and torque, without considering the saturation limit of the actuator, so when applied to actual engineering, when the underactuated surface ship is operating at sea, due to the initial tracking If the error is large, the force and torque transmitted by the controller output to the actuator may exceed its limited range. At this time, the system will produce a large overshoot, and the oscillation will be obvious, resulting in a decrease in the control performance of the system, and even tracking The instability of the control system is not conducive to the accurate path tracking of the underactuated surface ship, and even affects the completion of the ship's offshore operations

Therefore, it is of great significance to consider the path tracking control problem of underactuated surface ships under the condition of actuator input saturation and tracking error constraints, and it also brings great challenges to researchers

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